An ultrasound diagnostic system has become an important and popular diagnostic tool since it has a wide range of applications. Specifically, due to its non-invasive and non-destructive nature, the ultrasound diagnostic system has been extensively used in the medical profession. Modern high-performance ultrasound diagnostic systems and techniques are commonly used to produce two or three-dimensional diagnostic images of internal features of an object (e.g., human organs).
The ultrasound diagnostic system generally uses a wide bandwidth transducer to transmit and receive ultrasound signals. The ultrasound diagnostic system forms images of human internal tissues by electrically exciting an acoustic transducer element or an array of acoustic transducer elements to generate ultrasound signals that travel into the body. The ultrasound signals produce ultrasound echo signals since they are reflected from body tissues, which appear as discontinuities to the propagating ultrasound signals. Various ultrasound echo signals return to the transducer element and are converted into electrical signals, which are amplified and processed to produce ultrasound data for an image of the tissues. The ultrasound diagnostic system is very important in the medical field since it provides physicians with real-time and high-resolution images of human internal features without the need for invasive observation techniques such as surgery.
Recently, as the imaging technology in the ultrasound diagnostic system has evolved, a 3-dimensional ultrasound image can be provided. There is provided a static 3-dimensional ultrasound image as an example of the 3-dimensional ultrasound image. The static 3-dimensional image is conventionally produced by obtaining raw 3-dimensional data (e.g., data on a coordinate system (x, y, z) by using a 3-dimensional probe regardless of acquisition time) by: stacking frames upon one another at a uniform time interval to form consecutive frames; and processing the consecutive frames by using a 3-dimensional rendering technique. When the static 3-dimensional image is used for ultrasound diagnostic purposes, it is possible to perform accurate observations, diagnoses or treatments of the internal conditions of a human body without conducting complicated procedures such as invasive operations. Thus, the static 3-dimensional image is widely used. However, the static 3-dimensional image is not useful in observing a moving target object in real time such as an embryo in the uterus.
In order to overcome this shortcoming, a live 3-dimensional imaging method and apparatus for providing a 3-dimensional moving image (rather than the static 3-dimensional image) has been developed. The live 3-dimensional image consists of fewer frames than those of the real-time 3-dimensional moving image. Thus, it cannot show the complete movement of a moving target object. However, since the live 3-dimensional image consists of more frames than the static 3-dimensional image (e.g., 2 to 4 frames per second), it can show the movement of a moving target object more smoothly than the static 3-dimensional image.
Further, there has been an increased interest in the heart conditions of a fetus in order to perform an early diagnosis of the status of the fetus. However, since the systole and diastole of the heart are quickly repeated, it is impossible to scan all the movements of the heart just by using a 3-dimensional probe. Therefore, there is a problem in providing a real heartbeat image.